1. Technical Field of the Invention
The apparatus of the present invention relates to flexible cups utilized on downhole devices such as “pigs,” in a pipeline. More particularly, the present invention relates to an improved flexible cup, of the type used on “pigs” and other devices moved down the interior of a pipe line which are stronger and able to withstand high pressure thrusts against the device without deforming the flexible cups.
2. General Background of the Invention
When drilling for and producing subterranean oil and gas deposits and seeking out other energy sources, it is necessary to drill vertical, horizontal, curved or a combinations of such boreholes, and then to insert an elongated tube from the surface deep into a pipe or the open hole. Such drilled holes may be part of, for example, a well, pipe line, production line, or drill pipe, depending on the circumstances. Quite often it is necessary to insert a tube, whether it be continuous or segmented into the pipe or open hole, the tube having a diameter smaller than the diameter of the drill, production pipe or open hole, in order to remove or destroy blockages which have formed in the pipe or drilled hole.
It has become very beneficial in the cleaning or clearing of pipelines, or horizontal holes to utilize a continuous tubing, referred to as coiled tubing. The tubing is usually injected type tubing which is relatively flexible, and is of a continuous length being rolled off a large reel at the rig site and down hole. Various types of tools may be connected to the end of the coiled tubing to undertake whatever task is required below the surface. Coil tubing strings can be joined together up to and exceeding ten miles at a time.
When coil tubing is used in this manner, it is common that a “pig” will be placed at the end of the coil tubing. A pig is a device which is used to clear the passage within the pipeline. The pig is normally equipped with a plurality of cups around it perimeter, the circular cups being substantially the same of slightly less diameter than the interior of the pipeline, so that the cups make contact with the inner wall-of the pipeline as the pig is either forced along with fluid pressure or pull or pushed through the pipe line. Although, these cups are constructed of a strong, but flexible material, such as polyurethane, it has been found that due to the high pressures used, the cups may deform and lose their integrity within the pipeline, and not be effective in maintaining contact with the pipeline wall. Therefore, it would be beneficial to have a cup which may be constructed so as to withstand the high pressure from in front of or behind the cup, so that the cup is not deformed or damaged under high pressure conditions. Such cups, although quite common in “pigs,” may be used on a number of downhole devices in order to seal against the wall of the pipe as the device moves down the pipe. It should be made clear that although there has been a discussion of “pigs” being utilized at the end of coil tubing, it is quite common for “pigs” to be sent down a bore hole through various other means, and the present invention is as equally applicable to those types of “pig.”
Applicant is submitting herewith an information disclosure statement which includes additional prior art that applicant is aware of at this time.